This is from a previous "5 hidden features" email that Alex sent out to CN users:

3. Pin notes for easier scrolling You don't have to open note editor to read long notes. While you hold the spacebar key, all navigation commands - mouse wheel scrolling, arrow keys, Home, End, PgUp and PgDown keys operate on the text of the focused note instead of the note list. Try it out - pick a long note, press and hold the spacebar, and, for example, scroll the mouse wheel.

I'm not sure this is the same pinning that Mike has in mind.If you want to make some notes always appear on top, the only option to do that now is to sort by modified date in descending order, and set the modified date far into the future for notes that you want always on top.